Gap Inc. (GPS)’s Old Navy, the retailer’s biggest brand, has used 1990s stars from “Beverly Hills 90210” and New Kids on the Block in revamped marketing this year. Its latest addition is the Backstreet Boys.

The pop group will play at a free runway show tomorrow in New York’s Bryant Park, Old Navy’s first event during Fashion Week, and will feature them in commercials starting Sept. 19, said Michelle DeMartini, its head of adult merchandising and brand licensing. The unit’s sales are up in 2012, after sliding 4 percent to $5.67 billion in the year ended Jan. 28.

“Our target customer grew up in the ’90s, and that time period conjures an emotional connection,” DeMartini said in an e-mail. “In recent campaigns, we’ve worked with a number of actors and musicians who remind her of that nostalgic decade, such as Mr. T and Jordan Knight, and we’ve gotten really positive feedback.”

Old Navy’s use of nostalgia to connect with its core customer of 25- to 35-year-old women is a part of its new marketing platform implemented in November, and has included ads with Jennie Garth of “Beverly Hills 90210,” and Knight of New Kids on the Block. The brand, which accounts for about 39 percent of Gap’s revenue, changed course after confusing customers last year with original songs and music videos in its “Old Navy Records” campaign.

Rockstar Jeans The 4 p.m. to 8 p.m. event tomorrow will showcase shoppers modeling Old Navy’s Rockstar jeans to highlight their universal fit and the brand’s inclusiveness, while commercials for the jeans will feature the hit single “Everybody (Backstreet’s Back)” by the Backstreet Boys, DeMartini said. The show will be hosted by Jenny McCarthy, the former Playboy model who hosted MTV’s “Singled Out” television show in the 1990s.

“The Backstreet Boys are an iconic band beloved by our customers, and there’s a certain magic to how their reunion tour coincided with our campaign for the Rockstar jeans,” DeMartini said.

Gap, based in San Francisco, has surged 92 percent this year through yesterday as sales in the U.S. have advanced, including a 4 percent increase for Old Navy, its most affordable, family-friendly division.

The five-member Backstreet Boys, which rose to fame with hit singles such as “I Want it That Way” and “Quit Playing Games (With My Heart),” said recently they are reuniting with the return of singer Kevin Richardson, with plans to release a new album next year.